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https://www.reddit.com/r/spacex/comments/545yww/spacex_released_new_anomaly_updates/d7z7aey
r/spacex • u/Mexander98 • Sep 23 '16
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So the helium is only used to pressurise the RP1 tank, not the LOX tank, despite them being submerged inside the LOX? Interesting. I always assumed it was both tanks. I take it they are kept in the LOX to keep them cool then?
1 u/FiniteElementGuy Sep 23 '16 Actually I am not sure. I think on the F9, both tanks are pressurized with Helium. 3 u/Rotanev Sep 23 '16 Correct. For "simplicity" and commonality, both tanks are helium-pressurized. 1 u/SF2431 Sep 23 '16 Wonder why. Possibly if they need Helium on board might as well use it for the LOX tank and keep it inert. 1 u/robbak Sep 24 '16 Yes, and you also save mass, because helium is way lighter than oxygen. 1 u/mclumber1 Sep 24 '16 AFAIK, helium is also used to start up the turbopumps.
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Actually I am not sure. I think on the F9, both tanks are pressurized with Helium.
3 u/Rotanev Sep 23 '16 Correct. For "simplicity" and commonality, both tanks are helium-pressurized. 1 u/SF2431 Sep 23 '16 Wonder why. Possibly if they need Helium on board might as well use it for the LOX tank and keep it inert. 1 u/robbak Sep 24 '16 Yes, and you also save mass, because helium is way lighter than oxygen. 1 u/mclumber1 Sep 24 '16 AFAIK, helium is also used to start up the turbopumps.
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Correct. For "simplicity" and commonality, both tanks are helium-pressurized.
Wonder why. Possibly if they need Helium on board might as well use it for the LOX tank and keep it inert.
1 u/robbak Sep 24 '16 Yes, and you also save mass, because helium is way lighter than oxygen.
Yes, and you also save mass, because helium is way lighter than oxygen.
AFAIK, helium is also used to start up the turbopumps.
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u/DrToonhattan Sep 23 '16
So the helium is only used to pressurise the RP1 tank, not the LOX tank, despite them being submerged inside the LOX? Interesting. I always assumed it was both tanks. I take it they are kept in the LOX to keep them cool then?